Your Own Microbiology Laboratory

A Good Plan for Starting Bacteria Experiments.

You don't need any special equipment to begin working with bacteria, or yeasts, or molds. If you look around you, you will find cultures of bacteria already growing. If you check several discarded milk jugs you are likely to find that most stink due to the growth of bacteria. Many of the jugs will contain spoiling milk of different colors due to different bacteria being present. Perhaps a tenth of the jugs will contain greenish or bluish milk. Such milk is often a nearly pure culture of Genus Pseudomonas. Working with such spoiling milk can be an interesting project, but you should read about bacteria safety first.

I suggest you begin learning about microbes by working with some safe ones. Baking yeast that you can buy at the grocery store is a good place to begin because you can learn much microbiology using baking yeast. See page b021.htm. That experiment gets you started learning what microbes need to grow. Learning what food and culture conditions produce the best growth in one of the main things that professional microbiologists do. You can plan and complete experiments using foods available from your kitchen, garden, lawn, or farm to learn much about proper nutrition for microbes.

I might be helpful to read pages B026-28 before you begin any experiments because those pages tell you how to make some useful media from kitchen items, dispense into bottles, sterilize, and store, and use. Then begin some simple experiments such as B021. Doing a few experiments will help you l learn what supplies you need. You can do plenty without buying anything. Later you may want to buy some supplies, but at first see how much you can do with items from your home, farm, and gifts of discarded items.

Approximate Conversions

I have made the following measurements to help you. You may not have access to balances to weigh things. You may not have graduates or pipets to measure volumes. You will find the metric system used in a science books and on this web sites. This list of approximations should be very useful. As a beginner do not be too worried about your lack of fine measuring devices. Approximations will work fine. Don't let the lack of equiptment delay your science projects. Find substitutes.

Using Kitchen Measuring Spoons

Often you will need a certain number of grams of a substance. I plan to weigh several common substances so you can easily mix media with acceptable precision. I used a staight edge such as a knife to strike off the excess so that I had exactly level spoonsfull. Cooks work the same way. The call these level spoonsfull.

Table Sugar is pure sucrose
1/4 teaspoon of table sugar packed = 1.10 grams
1 teaspoon of table sugar packed = 4.35 grams; not packed = 4.25 grams
1 tablespoon of table sugar packed = 13.0 grams; not packed = 12.6 grams
This was the normal size grains of table sugar I bought at the grocery store

I will do the same for table salt, corn starch, water, and other foods.

Useful Salvage

Volumetric Tools. Find two 500 ml pop bottles. Fill one to the neck with water. Now pour some of that water into the second identical bottle until both are equally filled. Mark that level as 250 ml on each bottle. Discard the water from one bottle. Now repeat using 250 ml of water and mark the 125 level on each bottle. Find a 1 liter pop bottle, take it to school and use a 100 ml graduate to pour 100 ml of wter into it and mark the level as 100. Add 100 ml more water, and mark 200. Continue workling very carefully until you have a homemade 1 liter graduate. You can similarly mark 5 ml, 10 ml, 15 ml, 20 ml, 30 ml on culture tubes or any small bottle. These tools are plenty good for a home lab and will make a good addition to your science fair exhibit.


Build a small balance by making a hole in the middle of a stick and hanging it by a string. Use wire to hang pans on each end and you have a good balance that cost nothing. For weights, cut wire to the correct length and file to exact weight. Or use BBs or lead shot as weights and determine their weight at shool on a good balance. Test your balance by move the loads to the opposite pans. If still in balance then your balance arms are equal.

My Own Experiences

Like many kids, I did many science experiments at home at an early age. Since then I have worked in many university laboratories, but working in those expensive labs with marvelous equipment was not much greater thrill than working at home with household items and tools I built. Best of all it was my years of experience working at home as a youngster that got the professors interested in my abilities and led to the invitation to work at Purdue University, California Institute of Technology, and other fine research institutions. If you have fun with your home experiments, you will have science professors just as interested in recruiting you to work in their labs as a college basketball coach will be interested in the player who works hard at learning basketball.

When I became a highschool biology and chemistry teacher, the skills I developed as a kid enabled me to build things to improve my teaching. I am was repaid over and over by the appreciation of my students for the experiments they were able to do. Any time we needed something, a student was usually able to build it in his shop class. You can do the same.

Rule #1. Don't waste too much time wishing for equipment you don't have. Spend your time thinking about things you can do with what you have.

I love working with bacteria, yeasts, fungi, protozoa, algae, and bacterial viruses at home. The study of these things is called microbiology. The study of these different organisms uses approximately the same equipment. While this series of pages B020 => B039 will concentrate on the supplies and equipment for studying bacteria, Most of these supplies, equipment, and methods will be useful for studying other microbes. Later, I will write pages about the equipment to study the other organisms.

I have used all the homemade items mentioned in this website. I know they are satisfactory.

First draft = 98 Jan 26; Revision #2 = 98 March 11
Written by Harold Eddleman, Ph. D., President, Indiana Biolab, 14045 Huff St., Palmyra IN 47164